Cap for palletised loads

ABSTRACT

A cap for use on a palletized load has a main moulding providing housings at a pair or two pairs of opposite sides for a cassette in which a strap passes through a slotted crossbar between a drum and a hook having two prongs for engaging the underside of the platform of a pallet (e.g. at each side of a middle spacer), the strap then being tensioned by a linkage between the slotted crossbar and a lever within a slot for swinging between an inoperative position and an operative position (e.g. up to 90° thereto) to rotate the crossbar to wind the strap thereon.

RELATED/PRIORITY APPLICATION

This application is a National Phase filing regarding InternationalApplication No. PCT/GB2004/002166, which relies upon British ApplicationNos. 0312791.7 and 0322549.7 for priority.

BACKGROUND OF THE INVENTION

This invention relates to a cap for use on palletised loads, moreparticularly the type of cap having at least two strapping strandsretractable into housings through openings at opposite sides (at least)of the cap, spring means within the housings for retracting thestrapping strands, hooks on the free ends of the strapping strands forengagement with the underside of the platform of a pallet (e.g. a 2-wayor 4-way pallet), tensioning means within the housings for tighteningthe strapping strands between the cap and the pallet after interposing aload between the cap and the pallet, and stop means for limitingretraction of the hooks into the housings when not engaged with apallet.

Such a cap can be used without need to modify existing pallets,particularly—but not exclusively—those made of wood. The preferred formof hook has two prongs spaced apart so as to fit one to each side of amiddle spacer of a pallet, without being in danger of damage ordislodgement by the forks of a fork-lift truck.

Two such caps are to be found in WO-A-01/96203.

In one of those caps each strapping strand is a wire or non-metallicrope retractably wound spirally on a ‘thin’ reel within the respectivehousing and having a short cylindrical core between annular flangesspaced apart by negligibly more than the overall diameter of the rope,so that the rope will be wound spirally on the core, the axis of thereel being perpendicular to the general plane of the cap, the core beingon a shaft rotatably mounted within the housing, there also beingprovided a rewind spring coiled round the shaft alongside the reel, stopmeans limiting the extent to which the hook can be drawn into thehousing by the action of the rewind spring, a ratchet concentric withthe reel and rotatable with the reel and shaft, with a pawl for engagingteeth on the ratchet to stop or prevent pulling of the rope from thereel, and manually-operable means for tensioning the rope when the pawlhas been engaged with a tooth on the ratchet, particularly characterisedin that each tooth of the ratchet has a pawl-engageable face inclinedforwardly from its radially inner end with respect to a radial line fromthe axis of the shaft through said radially inner end of said face andwith respect to the direction of unwinding of the rope from the reel,the pawl has a complementary face for mutual engagement with said faceof any one tooth of the ratchet, the pawl is provided withspring-loading means with manually-operable means for changing theeffect of the spring loading over between urging the pawl intoengagement with the ratchet and towards a position holding the pawlclear of the ratchet, and in that the manually-operable tensioning meansis by way of a separate wrench engageable with one end of the shaft.While the reel can accommodate an adequate length of rope; and aseparate wrench can have such a length of handle as to enable adequatetension to be applied to each wire or rope, application of the wrench tothe cap when placed on a load of a height of, say, two metres is verydifficult, even for a person of above average height. Likewise, accessto the manually-operable change-over means for the ratchet is verydifficult, especially as the change-over cannot be effected without useof the wrench for slight additional tensioning of the wire or rope tofree the pawl from the ratchet.

In the other cap each strapping strand is a strap, there being withinthe respective housing parallel guides between ends of the housing, atone end of which is the opening; a crosshead slidable along the guidestowards and away from the opening, the crosshead being mainlyconstituted by crossbars of graduated diameters; a fixed array ofgraduated crossbars adjacent the opposite end of the housing from thecrosshead, the axes of the crossbars in the crosshead and the fixedarray all being in a common plane with the smallest diameter crossbarsbeing the nearest to each other, the strap having its inner end securedto one of the smallest diameter crossbars and being lapped inmulti-purchase array round the other smallest diameter crossbar and eachsuccessively greater diameter crossbar in the crosshead and fixed arrayin turn, and with the final lap of the strap emerging from the openingin the housing, and spring means to urge the crosshead away from thefixed array; the total length of strap that can be accommodated beingprincipally dependent on the number and lengths of laps between thecrosshead and the fixed array, and the number of laps being determinedby the number of crossbars in the crosshead and in the fixed array (e.g.three crossbars in one and two in the other giving five laps), thediameters of the crossbars can be but a few millimetres each consistentwith being strong enough to carry the loads in the strap generated bythe spring means, the tensioning means being a lever with an over-centrelocking action rotating a slotted crossbar through which the strappasses. The length of strap that can be accommodated is very limited;and the length of the lever and the extent to which it can rotate theslotted crossbar are so limited that adequate tension in the straps isdifficult to achieve, especially in view of elasticity/stretchability ofthe straps.

BRIEF SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a cap forpalletised loads with which adequate tension can be applied to thestrapping strands by means accessible at all times from the sides of thecap.

According to the present invention, a cap of the type initially definedhas each tensioning means comprising a slotted crossbar through whichthe strapping strand passes, a lever pivoted within the respective sideof the cap and movable in a plane parallel to the general plane of thecap between operative and inoperative positions and linkage between thelever and the slotted crossbar such that movement of the lever frominoperative position to operative position causes rotation of theslotted crossbar to wind the strapping strand round the slottedcrossbar, thus enabling tension to be developed in the strapping strandafter its hook has been engaged with a pallet, together with manuallyreleasable spring-loaded latch means for securing the strapping strandin tension. Thus the lever is accessible from the respective side of thecap regardless of the height at which the cap is disposed on a load on apallet.

The latch means may also hold the lever in inoperative position;alternatively, a return spring may be provided to urge the lever toinoperative position.

The axis of rotation of the slotted crossbar may be at the middle of theslot or offset therefrom. The slotted crossbar may be formed by a pairof parallel bars rigidly connected at both ends, and the axis ofrotation may be at the middle of one of the bars, whereby the other barorbits round it.

The extent of rotation of the slotted crossbar, and hence the tension inthe strapping strand, may be determined by the mechanical advantage ofthe lever and the form of linkage between the lever and the slottedcrossbar. Thus the linkage may comprise at least one wire or,preferably, wire rope for its strength, flexibility and durability, orsubstantially non-extensible non-metallic mono-filament or strandedcable (hereinafter referred to simply as “wire”, but “wire rope” in theparticular embodiment to be described with reference to the accompanyingdrawings) secured at one end to the lever and secured at the other endto a pulley secured for rotation with the slotted crossbar, movement ofthe lever from inoperative position to operative position effectingunwinding of the wire from the pulley to cause winding of the strappingstrand round the slotted crossbar; the ratio of the diameter of thepulley to the crossbar thus affords a high mechanical advantage capableof developing high tension in the wire (and hence in the strappingstrand after its hook has been engaged with a pallet); with a springreturn for re-winding the wire onto the pulley when the lever is movedto effect release of tension in the wire. The wire (or cable) may beformed of metal or of any other substantially inelastic/non-extensiblematerial.

A ratchet mechanism is preferably incorporated in the linkage betweenthe lever and the slotted crossbar, to enable repeated swinging of thelever to-and-fro to effect as many turns of the strapping strand roundthe slotted crossbar as may be needed for adequate tensioning of thestrapping strand and holding that tension.

The lever and ratchet mechanism may be based on a well-known type ofdevice for tensioning a strap for securing a load on a lorry or a strapon a side sheet for protecting a load on a lorry, in which device thestrap is wound round a spool between two arms of a bifurcated lever, aratchet being provided between each end of the spool and the respectiveadjacent arm, the lever arms and spool and ratchets being mounted on acommon pivot in a mounting frame, with the ratchets secured for rotationwith the spool and the lever rotatable with respect to the spool andratchets, a drive plate slidably mounted on the lever, a first springurging the drive plate into engagement with the ratchet to enableto-and-fro swinging of the lever to wind the strap round the spool andtension it, a second spring urging the latching plate into engagementwith the ratchet to latch the ratchet at times when it is not beingrotated by driving action of the lever through the drive plate, thedrive plate being manually operable against the first spring todisengage it from the ratchet, and a cam on the lever for disengagingthe latching plate from the ratchet after the drive plate hasencountered and rides along a radius plate fixed in the mounting to holdthe drive plate clear of the ratchet when unwinding of the strap fromthe spool is required.

Such a device is usually wholly or principally of metal construction,with coil compression springs for the drive plate and the latching plateand could be adapted for incorporation in a cap as described above by,instead of the strap being wound on the spool, a circumferential grooveis provided in the spool in which is reeved and wound one end of thewire (or cable) the other end of which is secured to the pulley foreffecting rotation of the slotted crossbar on to which the strappingstrand is wound.

However, the lever and ratchet mechanism is preferably formed wholly orprincipally with parts moulded in plastics material, with resultingpotential for reducing costs and weight and also number of components.

Therefore, there is preferably provided a bifurcated lever, a spool witha ratchet extending from one end to a circumferential groove adjacentthe other end into which the wire (or cable) is reeved, the lever andthe spool being rotatable about a fixed common axis in the housing andthe lever being rotatable with respect to the spool, a ratchet drivepawl on a first resilient arm mounted in the lever, a latching pawl on asecond resilient arm mounted in the housing to latch the ratchet attimes when it is not being rotated by the driving action of the leverthrough the drive pawl, a fixed stop in the housing for limitingswinging of the lever (for example to 90°) from inoperative position,manually operable means for disengaging the drive pawl from the ratchet,and a cam on the lever for disengaging the latching pawl from theratchet after the drive pawl has encountered and rides along a fixedradius plate in the housing beyond the stop means.

A spring is preferably provided to return the lever to inoperativeposition automatically, which spring is conveniently a torsion springcoiled about the lever and spool pivot and with end arms abuttingprojections on the lever and within the housing respectively; thus thisspring is, along with the wire reeved to the spool in thecircumferential groove, one of the only two metal parts required in thelever and ratchet mechanism.

The manually operable means for disengaging the drive pawl from theratchet may comprise a slider movable in the lever towards and away fromthe drive pawl, with a head on a neck passing through a slot in thefirst resilient arm, the head having lateral projections engaging rampson each side of the slot when the slider is moved towards the drivepawl; there preferably also being a fixed abutment in the housing spacedfrom the fixed stop to be engaged by the slider to urge it back towardsits inoperative position as the drive pawl rides along the radius plate.

It is preferable to ensure that the latching pawl cannot beunintentionally disengaged from the ratchet (e.g. through vibrationduring transporting of a capped load on a pallet) and this may beeffected by providing a plate or spaced abutments on the lever to liealongside the second resilient arm when the lever is moved intoinoperative position.

Torque limiting means may be incorporated in the lever to ensure thatthe wire (or cable) cannot be overloaded.

Each strapping strand is preferably a strap having its end remote fromthe hook secured to the barrel of a drum, with a spring within the drumfor retracting the strap when it is free to run through the slottedcrossbar. The drum may be on an axis perpendicular to the general planeof the cap, in which case the strap twists through 90° between the drumand the slotted crossbar. Thus each housing need have a depth littlemore than the height of the drum, which preferably has thin flanges atthe ends of its barrel.

Each hook preferably has two prongs spaced apart so as to fit one toeach side of a middle spacer of a pallet.

Each opening is preferably provided at the back of a recess in therespective side of the cap of a depth front-to-back to receive fully therespective hook, and the bottom of the recess provided with rampingsurfaces to effect automatic parking of the hook into the recess uponretraction of the strap into the housing and retention of the hookagainst dislodgement if the cap is turned over; and the lever is locatedwithin a slot in the respective side of the cap extending from therecess.

To suit different widths of middle spacers in pallets, e.g., standardwooden pallets, euro pallets and specific user pallets, hooks ofdifferent sizes may be made available with different spacings betweenthe prongs, for location closely to each side of the respective widthspacer, each prong being cranked out from a mid-portion of the hook of awidth commensurate with the width of the strap secured around it.Alternatively, a single size of hook may be provided with a spacingbetween the prongs for location closely to each side of the widestmiddle spacer in use. Each hook is preferably provided with a bracingbar parallel to the mid-portion to aid placement onto a pallet by thetoe of footwear of a user. The bracing bar may be pulled by the fingersof a user for effecting withdrawal of the hook from its recess;alternatively, the strap may extend beyond the bracing bar for graspingby a user's hand, or the strap may terminate at the mid-portion of thehook and a separate tab provided on the bracing bar.

The bulk of the cap is conveniently formed of plastics material, with amain moulding forming a lower portion, upstanding sides and dependingskirt, one or more mouldings forming an upper portion, and with integralwall formations on the upperside of the lower portion defining thehousings, and providing axles for the drums and guides for the strapsfrom the drums to the slotted crossbars. The skirt is preferably steppedoutwardly from side portions of the cap to enable like caps to be nestedwith each other and/or with pallets during return transporting as wellas to help secure a load on a pallet by embracing the top sides of theload.

The underside of the cap is preferably slightly domed, i.e. it isslightly lower (e.g. by 6.0 mm) at the corners than at the centre, or isprovided with pads (e.g. 120.0 mm square and 6.0 mm thick) adjacent thecorners, so that with strapping strands at the middle of sides of thecap under tension tending to cause bowing, the doming or pads willdistribute the loading of the cap more evenly across the top of the loadon the pallet to which the cap is applied and the straps are hookedrespectively.

Each set of lever, spool, slotted crossbar, etc. together with recessand ramping surfaces may be provided in a cassette having a chassis anda cover, with upstanding formations on the chassis and dependingformations on the cover mating to form bearings for the slotted crossbarand pulley.

The centre of the upper portion of the cap may be provided with anopening spanned by a bar handle, to facilitate manual handling of thecap by one hand of an operator, particularly onto and off loads onpallets, the central opening preferably being located above a continuouswall upstanding from the lower portion, to prevent water or dirtentering the space between the mouldings occupied by the strappingmechanisms; alternatively, or in addition, one or more handholds may beprovided at each side of the cap, or on top adjacent each corner, toallow the other hand of an operator to steady or control manipulativemovement of the cap, e.g. a slot in each side of the skirt; or the skirtround all sides of the cap may suffice as a handhold anywhereconvenient.

While a cap with two strapping strands may suffice for use with a 2-waypallet or a 4-way pallet, a cap according to the present invention mayhave four strapping strands especially for use with a 4-way pallet butcapable of being used with a 2-way pallet by utilising only two oppositestrapping strands or all four.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention and a modification thereof will now bedescried, by way of example only, with reference to the accompanyingdrawings in which:

FIG. 1 is a view from above of a cap in accordance with the invention;

FIG. 2 is an underneath view of the cap of FIG. 1;

FIG. 3 shows the cap of FIGS. 1 and 2 in use securing a load on apallet;

FIG. 4 is a fragmentary view showing in more detail one of the hooksseen in FIG. 3 engaged with the platform of the pallet;

FIG. 5 is a view from above of the main moulding forming the lowerportion of the cap;

FIG. 6 is an underneath view of one of the two mouldings forming theupper portion of the cap;

FIG. 7 is a view from below of the handle member seen in FIGS. 1 and 3secured between the mouldings forming the lower and upper portions ofthe cap;

FIG. 8 is a fragmentary view showing the handle member in place in themain moulding;

FIG. 9 is a view from above of a form of cassette fitting into two (ormore) opposite housings in the main moulding seen in FIG. 5;

FIG. 10 corresponds to FIG. 9 but with the cover of the cassette removedand the mechanism in operative condition;

FIG. 11 is a view from above of the chassis of the cassette of FIGS. 9and 10;

FIG. 12 is an underneath view of the cover of the cassette;

FIG. 13 is a view from above of the drum seen in FIGS. 9 and 10;

FIG. 14 is a fragmentary view showing part of the drum with a portion ofits cover broken away to show a strap attached thereto and partiallywound thereon, and also showing a rewind spring for the drum;

FIG. 15 is a view of the spindle seen in FIGS. 9 and 10 as viewed in anopposite direction;

FIG. 16 is a view of a rewind spring for the spindle;

FIG. 17 is a view from the front and above of a lever seen in FIGS. 1 to3 and FIGS. 9 and 10;

FIG. 18 is an underneath view of the lever;

FIG. 19 is a view from the front and below of the release slider seen inprevious views of the lever;

FIG. 20 is the opposite view of the release slider;

FIG. 21 is a view from the rear and below of a driving pawl forincorporation in the lever;

FIG. 22 is a view from the rear of the lever with the release slider anddriving pawl incorporated;

FIG. 23 corresponds to FIG. 22 but shows the slider in itspawl-releasing position;

FIG. 24 is a view from below of a spool with a ratchet for incorporationin the lever;

FIG. 25 is a view of a return spring for the lever;

FIG. 26 is a view of a cable with ferrules for attachment to the spindleand spool respectively;

FIG. 27 is a fragmentary horizontal section through the lever showingthe lever and ratchet mechanism in inoperative condition;

FIG. 28 corresponds to FIG. 27 but shows the lever and ratchet mechanismin operative condition;

FIG. 29 corresponds to FIGS. 27 and 28 but shows the lever and ratchetmechanism in drive pawl-releasing condition; and

FIG. 30 corresponds to FIG. 29 but shows the lever and ratchet mechanismin latching pawl-releasing condition;

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The cap 1 shown in FIGS. 1 and 2 is for use in securing palletizedloads, such a load 2 being shown in FIG. 3 secured on a pallet 3 by thecap, which has a lower portion 4 with upstanding sides 5 and dependingskirt 6 (for embracing the top sides of the load) (and also enablingcaps to be nested with each other or with pallets) formed by a mainplastics moulding (see also FIG. 5) and an upper portion 7 shown formedby two plastics mouldings 8 (see also FIG. 6), but which could be formedas a single moulding, in which case there would not be mating edges atthe lines 9.

Integral wall formations 10 on the upperside of the lower portion 4 ofthe cap define housings 11 for cassettes 12 (see FIGS. 9 to 12)containing retractable straps 13 on free ends of which are hooks 14 (seealso FIG. 4) each having two prongs 15 spaced apart so as to fit one toeach side of a middle spacer 17 of a pallet (see particularly FIG. 4)with the prongs engaging the underside of the platform 18 of the pallet,so that the straps 13 can be tensioned by mechanisms within thecassettes (to be described in detail presently) upon operation of levers19 which can be seen, along with the retracted hooks 14, in FIGS. 1 and2 in gaps 20 in the sides 5 of the lower portion/main moulding 4.

The hook 14 is provided with a bracing bar 16 parallel to a mid-portion14M of the hook to which the strap is secured, to aid placement on to apallet by the toe of footwear of a user, and a tab 13A formed by aportion of strap is secured to the bracing bar to extend beyond the side5 of the cap 1 for grasping by a user's hand, for withdrawal of the hookand strap from the cap.

FIGS. 1 to 3 indicate the inclusion of straps 13 and levers 19 (incassettes 12) on all four sides 5, but two straps, etc., on oppositesides may suffice, in which case the gaps 20 in the other two oppositesides can be closed by blanking-off strips, not shown.

A central pocket 21 (see FIG. 5) is formed in the main moulding 4 by twoupstanding wall formations 22 between portions 10A of the wallformations 10, and notches 23 are provided in the wall formations 22 toreceive an I-shaped handle 24 (see also FIGS. 7 and 8) which isaccessible through an opening 25 formed between the mouldings 8. Furtherpockets 26 are formed by further upstanding wall formations 27 near thecorners 28 of the main moulding 4 to register with openings 29 in themouldings 8 to provide additional handholds for steadying the cap 1 whenbeing placed on or lifted off a load by a hand grasping the handle 24.

The mouldings 8 are secured by screws 30, 31 into pairs of pillars 32,33 respectively within the housings 11 in the moulding 4, and the pairsof pillars 32 also serve to locate the cassettes 12, as will bedescribed presently. Depending formations 34 on the underside of themouldings 8 interdigitate with further upstanding formations 35 withinthe housings 11 to stiffen the assembled cap. Raised areas 36 areprovided on the mouldings 8 for location within the base of anotherpallet (not shown) placed on the cap.

Tensioning means for each strap 13 comprises a crossbar 37 (see FIGS. 9and 15) with a slot 38 through which the strap 13 passes, and linkage 39to the lever 19 whereby movement of the lever from inoperative position19(A) (FIGS. 9 and 27) to operative position 19(B) (FIGS. 10 and 28)causes rotation of the slotted crossbar, to effect winding of the strapround the crossbar, as is evident at 13W in FIG. 10, thus enablingtension to be developed in the strap after the prongs 15 of its hook 14have been engaged with a pallet.

The linkage 39 will now be described in detail.

The slotted crossbar 37 is provided at one end of a spindle 40 havingjournals 41, one adjacent each end of the slot 38 and a third at theother end of the spindle, adjacent a pulley 42. A chassis 43 of eachcassette 12 (see particularly FIG. 11) is provided with upstandinghalf-bearings 44 for the journals 41 and a cover 45 of the cassette (seeparticularly FIG. 12) has the other halves 46 of the bearings dependingtherefrom. The chassis 43 has hollow upstanding formations 47 forlocation on the pillars 32 on the main mouldings 4 of the cap 1. A coilspring 48 (FIGS. 9, 10 and 16) encircles a ribbed portion 49 (FIG. 15)of the spindle and has a limb 50 at one end to engage a small hook-likeprojection 51 on the pulley, while a bent limb 52 on the other endengages a recess (not visible) in the base of chassis, the spring 48being effective to urge the slotted crossbar 37 to the position shown inFIG. 9 when tension in the strap 13 is to be released.

A wire rope 53 (FIGS. 10 and 26) has a ferrule 54 at one end forengagement in a socket 55 in the pulley 42, and the wire rope has anumber of turns wound on the pulley (as indicated in FIGS. 9 and 10),while the other end of the wire rope is provided with a ferrule 56 forengagement in a counterbore 57 in a bore 57A opening into a groove 58adjacent one end of a spool 59 (see FIG. 24) having a ratchet 60extending from the other end to the groove. The spool is rotatable alongwith and with respect to the lever 19 on a fixed common axis 61 providedby pivot portions 62A, 62B on the chassis 43 and the cover 45respectively, the lever being bifurcated to provide upper and lowerflanks 63, 64 respectively (see particularly FIGS. 17, 18, 22 and 23)between which the spool 59 is disposed. The upper flank 63 of the lever19 has a projection 65 for engagement by a limb 66 at one end of a coilspring 67 (see FIG. 25), while the underside of the cover 45 of thecassette has a projection 68 for engagement by a limb 69 at the otherend of the spring 67, the spring thereby being effective to urge thelever 19 towards inoperative position, in which position a bar 70 on theunderside of the lever 19 abuts a bar 71 on the base of the chassis 43.

The lever 19 contains a drive pawl 72 (see FIGS. 21 to 23 and 27 to 30)for the ratchet 60 on a first resilient arm 73, while the chassis 43carries a latching pawl 74 (see also FIGS. 10 and 11) on a secondresilient arm 75 so that when the lever 19 is oscillated between thepositions shown in FIGS. 9 and 10 (or FIGS. 27 and 28) the drive pawlrotates the ratchet/spool 59 to wind the wire rope 53 into the groove 58in the spool, thus winding the wire rope from the pulley 42 and,therefore, rotating the spindle 40 to wind the strap 13 on to theslotted crossbar 37 (as seen at 13W in FIG. 10), and the latching pawl74 holds the ratchet/spool while the lever 19 returns, under the urge ofthe spring 67 to the position shown in FIG. 9. The lever 19 has twospaced abutment portions 76 to lie alongside the second resilient arm 75when the lever is moved into the position shown in FIG. 9, to ensurethat the latching pawl 74 cannot be unintentionally disengaged from theratchet 60 through vibration during transporting of a capped load on apallet

Further details of the lever 19 and their purpose will be describedlater with particular reference to FIGS. 27 to 30 in addition to FIGS.17 to 23.

Each strap 13 has its end 77 remote from the hook 14 secured to thebarrel 78 of a drum 79 (see FIGS. 9 to 11, 13 and 14) on an axis 80perpendicular to the general plane of the cap 1, with a clock spring 81within the drum for retracting the strap when it is free to run throughthe slotted crossbar 37, i.e., when in the position shown in FIG. 9, andthe strap twists through 90° between the drum and the slotted crossbarafter turning round a guide post 82. Thus each housing 11 has a depthlittle more than the height of the drum 79, which has thin flanges 83A,83B, the former being formed integrally with the drum while the latteris formed by a peripheral margin of a cover 84 with a snap-fitting (notvisible) to the barrel of the drum, a cut-out 85 being formed in thecover for insertion or removal of the strap end 77 to or from an anchorpost 86 within the barrel 78.

From the slotted crossbar 37 the strap 13 passes through an opening 87provided at the back of a recess 88 of a depth front-to-back in the side5 of the cap 1 to fully receive the respective hook 14, and the bottomof the recess is provided with ramping surfaces 89, 90 to effectautomatic parking of the hook into the recess upon retraction of thestrap into the housing and retention of the hook against dislodgement ifthe cap 1 is turned over, and the lever 19 is located, when ininoperative position, within a slot 91 in the respective side 5 of thecap extending from the recess. It will be evident that the recess 88constitutes stop means for limiting retraction of the hook 14 into thehousing 11 when not engaged with a pallet.

Depending V-shaped spring fingers 92 (see FIGS. 9 and 12) on the cover45 of the cassette 12 make snap engagement with projections 93 on thechassis 43 and an inverted V-shaped spring finger 94 upstanding from thechassis 43 makes snap engagement with a projection that is not visiblebeing on the far side of an L-shaped post 95 (FIG. 12) depending fromthe cover, to secure the cover on the chassis after the lever andratchet mechanism etc has been inserted. Spring fingers 96 on thechassis 43 make snap engagement with notches 97 in the walls 10 of themain moulding 4 of the cap 1 at the ends of the gaps 20 (seeparticularly FIG. 5).

Turning now to FIGS. 17 to 23, the first resilient arm 73 carrying thedrive pawl 72 is divided by a long slot 98 and the divided ends 99 are asnap-fit into a block 100 formed integrally within the lever 19, butonly after insertion of a slider 101 through an aperture 102 in theouter face 103 of the lever, the slider having an angled corner 104matching one side 105 of a V-shaped end to the aperture 102 tofacilitate insertion of the slider. The slider is provided with a head106 on a neck 107 passing through the slot 98 in the arm 73, the dividedends 99 of the arm 73 being inserted either side of the neck on thealready inserted slider and then into the block 100. The head 106 haslateral projections 108 engaging ramps 109 on each side of the slot 98when the slider is moved towards the drive pawl 72 to disengage thedrive pawl from the ratchet 60.

With the slider in the position shown in FIGS. 17 and 22 and as also inFIGS. 27 and 28, the drive pawl 72 is in engagement with the ratchet,thus enabling the lever 19 to be swung repeatedly between the positions19(A), 19(B) to rotate the spool 59, the position 19(B) being determinedby the drive pawl meeting a fixed stop 110 (see also FIG. 11) on thebase of the chassis projecting up through an arcuate slot 111 in thelower flank 64 of the lever, the actual contact being between the stopand a small heel 112 projecting downwards from the drive pawl 72.

The stop 110 is at one end of a radius plate 113 along which the shoeruns when with the slider 101 moved to the position shown in FIGS. 23and 29 the lateral projections 108 of the head 106 engage the ramps 109on the resilient arm 73 to flex it and disengage the drive pawl 72 fromthe ratchet 60, and the lever is moved towards a position 19(C) shown inFIG. 30 causing two things to happen. Firstly, the leading edge 114 ofthe slider 101 meets a fixed abutment 115 on the base of the chassisspaced from the fixed stop 110 to urge the slider back towards itsinoperative position, and, secondly, cam surfaces 116 on the lever 19flex the second resilient arm 75 to disengage the latching pawl 74 fromthe ratchet.

The consequence of this latter interaction is that the coil spring 48round the spindle 40 rotates the spindle to rewind the wire rope 53 onto the pulley 42 and, therefore, unwind it from the ratchet spool 59,and also rotate the slotted crossbar 37 to release the tension in thestrap 13 thus allowing the hook 14 to be pulled clear from the platform18 of the pallet 3. When the slotted crossbar has returned to theposition shown in FIG. 9 and the strap has been completely unwound fromit, the strap is then free to be rewound on to the drum 79 by the clockspring 81 and the hook 14 drawn back into the recess 88, guided by theramping surfaces 89, 90.

Finally, when the lever 19 is released by the user, the coil spring 67returns the lever to the position shown in FIGS. 9 and 27.

The mechanism shown in the cassette 12 is capable of generating in thestrap 13 tension of the order of 175 kgs with but a few oscillations ofthe lever 19, the effort applied to which when moving it frominoperative position 19(A) to operative position 19(B) will at first bevery slight as the first turn of the slotted crossbar 37 takes up slackin the strap 13. The return spring 81 in the drum 79 plays no part ingenerating the tension in the strap 13, and its loading is so slightthat it offers little resistance to winding of the strap around theslotted crossbar. Because winding of the strap around the slottedcrossbar occurs from both directions, as indicated by the arrows on thestrap in FIG. 10, the build-up of turns on the slotted crossbar is rapidand the effort needed to move the lever from inoperative position tooperative position increases with each oscillation until resistance tofurther driving movement indicates that adequate tension has beengenerated in the strap.

The underside 117 (see FIG. 2) of the lower portion 4 of the cap 1 ispreferably slightly domed, i.e. it is slightly lower (e.g. by 6.0 mm) atthe corners than at the centre, so that, with straps 13 at the middle ofthe sides 5 of the cap under tension tending to cause bowing, the domingwill distribute the loading of the cap more evenly across the top of theload 2 on the pallet 3 to which the cap is applied and the straps arehooked respectively. However, because the doming is so slight it cannotbe illustrated, but an alternative of pads 118 is shown in broken linesin FIG. 2, which pads may be, say, 120.0 mm square and of 6.0 mmthickness.

Although, as mentioned previously, the provision of strapping strands,hooks and tensioning mechanisms in cassettes affords the option ofincorporating one pair or two pairs of cassettes in a cap for use onpallets of, say, 1000.0 mm by 800.0 mm, for use with smaller pallets thecap may be of a size incapable of accommodating tensioning mechanismsfor more than two strapping strands and hooks at a single pair ofopposite sides of the cap, in which case formations described previouslyas upstanding from the chassis 43 of the cassette 12 could be upstandingdirectly from each of only two housings in the lower portion (or mainmoulding) of the smaller cap, and formations previously described asdepending from the cover 45 of the cassette could depend directly from aunitary upper portion of the cap, with consequent saving in quantity,weight and cost of moulded components.

1. A cap for use on palletised loads, the cap being of the type havingat least two strapping strands retractable into housings throughopenings at opposite sides of the cap, spring means within the housingsfor retracting the strapping strands, hooks on free ends of thestrapping strands for engagement with the underside of a platform of apallet, tensioning means within the housings for tightening thestrapping strands between the cap and the pallet after interposing aload between the cap and the pallet, and stop means for limitingretraction of the hooks into the housings when not engaged with apallet, characterized in that each tensioning means comprises a slottedcrossbar through which a respective one of said strapping strandspasses, a lever pivoted within the respective side of the cap andmovable in a plane parallel to a general plane of the cap between anoperative position and an inoperative position, and a linkage betweenthe lever and the slotted crossbar such that movement of the lever fromsaid inoperative position to said operative position causes rotation ofthe slotted crossbar to wind the strapping strand round the slottedcrossbar, thus enabling tension to be developed in the strapping strandafter its hook has been engaged with a pallet, together with manuallyreleasable spring-loaded latch means for securing the strapping strandin tension.
 2. A cap as in claim 1, characterized in that the linkagecomprises at least one wire secured at one end to the lever and securedat the other end to a pulley secured for rotation with the slottedcrossbar, movement of the lever from said inoperative position to saidoperative position effecting unwinding of the wire from the pulley tocause winding of a respective one of said strapping strands round theslotted crossbar, and with a spring return for re-winding the wire ontothe pulley when the lever is moved to effect release of tension in thewire.
 3. A cap as in claim 1, characterized in that a ratchet mechanismis incorporated in the linkage between the lever and the slottedcrossbar, to enable repeated swinging of the lever to-and-fro to effectas many turns of said respective one of said strapping strands round theslotted crossbar as may be needed for adequate tensioning of thestrapping strand and to hold the tension.
 4. A cap as in claim 3,characterized in that the lever and ratchet mechanism is in the form ofa well-known type of device for tensioning a strap for securing a loadon a lorry or a strap on a side sheet for protecting a load on a lorry,in which device the strap is wound round a spool between two arms ofsaid lever, a ratchet being provided between each end of the spool andthe respective adjacent arm, the lever arms and spool and ratchets beingmounted on a common pivot in a mounting frame, with the ratchets securedfor rotation with the spool and the lever rotatable with respect to thespool and ratchets, a drive plate slidably mounted on the lever, a firstspring urging the drive plate into engagement with the ratchet to enableto-and-fro swinging of the lever to wind the strap round the spool andtension it, a second spring urging the latching plate into engagementwith the ratchet to latch the ratchet at times when it is not beingrotated by driving action of the lever through the drive plate, thedrive plate being manually operable against the first spring todisengage it from the ratchet, and a cam on the lever for disengagingthe latching plate from the ratchet after the drive plate hasencountered and rides along a radius plate fixed in the mounting to holdthe drive plate clear of the ratchet when unwinding of the strap fromthe spool is required, further characterized in that instead of thestrap being wound on the spool, a circumferential groove is provided inthe spool in which is reeved and wound one end of the wire the other endof which is secured to the pulley for effecting rotation of the slottedcrossbar on to which the strapping strand is wound.
 5. A cap as in claim3, characterized in that there is provided a spool with a ratchetextending from one end to a circumferential groove adjacent the otherend into which the wire is reeved, the lever and the spool beingrotatable about a fixed common axis in the housing and the lever beingrotatable with respect to the spool, a ratchet drive pawl on a firstresilient arm mounted in the lever, a latching pawl on a secondresilient arm mounted in the housing to latch the ratchet at times whenit is not being rotated by the driving action of the lever through thedrive pawl, a fixed stop in the housing for limiting swinging of thelever from said inoperative position, manually operable means fordisengaging the drive pawl from the ratchet, and a cam on the lever fordisengaging the latching pawl from the ratchet after the drive pawl hasencountered and rides along a fixed radius plate in the housing beyondthe stop means.
 6. A cap as in claim 5, characterized in that themanually operable means for disengaging the drive pawl from the ratchetcomprises a slider movable in the lever towards and away from the drivepawl, with a head on a neck passing through a slot in the firstresilient arm, the head having lateral projections engaging ramps oneach side of the slot when the slider is moved towards the drive pawl.7. A cap as in claim 6, characterized in that there is provided a fixedabutment in the housing spaced from the fixed stop to be engaged by theslider to urge it back towards said inoperative position as the drivepawl rides along the radius plate.
 8. A cap as in claim 5, characterizedin that there is provided a plate or spaced abutments on the lever tolie alongside the second resilient arm when the lever is moved intoinoperative position, to ensure that the latching pawl cannot beunintentionally disengaged from the ratchet.
 9. A cap as in claim 1,characterized in that each strapping strand is a strap having its endremote from the hook secured to a barrel of a drum on an axisperpendicular to said general plane of the cap and the strap twiststhrough 90° between the drum and the slotted crossbar, with a springwithin the drum for retracting the strap when it is free to run throughthe slotted crossbar.
 10. A cap as in claim 1, characterized in thateach opening is provided at the back of a recess in the respective sideof the cap of a depth front-to-back to receive fully the respectivehook, and the bottom of the recess provided with ramping surfaces toeffect automatic parking of the hook into the recess upon retraction ofthe strap into the housing and retention of the hook againstdislodgement when the cap is turned over; and the lever is locatedwithin a slot in the respective side of the cap extending from therecess.
 11. A cap as in claim 1, characterized in that the bulk of thecap is formed of plastics material, with a main molding forming a lowerportion, sides and a skirt, one or more moldings forming an upperportion, and with integral wall formations on the upperside of the lowerportion defining the housings, the skirt is stepped outwardly from sideportions of the cap to enable like caps to be nested with each otherand/or with pallets during return transporting as well as to help securea load on a pallet by embracing the top sides of the load.